This invention arose from an effort to improve the life of longitudinally extended direct immersion heaters, where relatively long lengths of resistance heating elements are supported from a side wall of a liquid container. Existing heating units of this type typically have heating elements joined to the supporting wall by brazing. Joining dissimilar metals in this manner subjects them to the possibility of joint failure due to thermal expansion of the materials and vibrational movement. Where the elements are mounted by brazing, the ends of the elements outside the liquid area must also be sealed to produce an explosion proof or liquid type seal. Such sealing materials again are subjected to material failure due to vibration and temperature changes. The present invention both minimizes vibration and improves the seal to assure longer element life under actual working conditions.